When selling prices of goods put on store counters are set, a clearance sale for cutting selling prices of perishable foods in particular in view of their expiration dates, discounting the prices and then selling the perishable foods is widely performed. An appropriate time for a store to start a clearance sale of perishable foods changes according to various conditions such as a day of a week, weather, a season and a temperature. A time to start a clearance sale is not fixed due to such a situation. Therefore, it is not easy for a client who purchases perishable foods from a store to efficiently find and purchase clearance foods (see Patent Literature 1).
Generally, there is service for transmitting information indicating that “you have discount prices” from store to clients when goods are sold at clearance prices, i.e., discount prices. For example, there is a “discount notification mail” provided as Web service of the Internet by Kakaku.com, Inc. (Kakaku.com is the registered trademark) (see Non-Patent Literature 1). By using such mail service, a client can learn information related to clearance goods, and use the information to purchase desired goods.